Field of the Invention
In simple squeeze bottles, consisting of a resiliently flexible squeeze bottle proper and a spout member threaded on the bottle neck, there is no barrier to the ejection of the liquid nor to the intake of air for relaxation of the bottle. However, the simple structure is hazardous or disadvantageous in several respects, e.g., if such a squeeze bottle dispenser with an open dispensing outlet is accidentally tipped over or dropped, the liquid contents will drain. The resulting spill may be very troublesome to clean up in the case of some liquids, such as greasy or sticky liquids and, in the case of other liquids, such as solvents, may damage the surface on which the spill occurs, or the spill may create a slippery hazard.
A variety of squeeze bottle outlet closure sealing arrangements have been devised in efforts to avoid or eliminate these defects of the simple basic structure. These prior art structures are satisfactory to some extent in rendering a squeeze bottle dispenser spill-proof by disposing a valved barrier in the outlet. However, none of these barrier structures appears to have been satisfactory since these structures typically greatly inhibit the expulsion of the contained liquid through the barrier, greatly retard the relaxation of the elastic squeeze bottle, or they may be prohibitively expensive. Thus, the device of Venable U.S. Pat. No. 3,674,183 involves a valve disc having a sinuous slit cut at an angle with respect to the face of the disc which, irrespective of its efficiency as a valve, appears impractical for purposes of mass production. Musher U.S. Pat. No. 3,410,460 discloses a barrier having a simple diametrically disposed slit which, if employed in a liquid dispenser bottle, would be totally impractical in too greatly inhibiting both dispensing of the contained liquid and admission of ambient air in order to permit relaxation of a squeeze bottle. For the same reasons, the various slit configurations of Flax French Pat. No. 1,203,220 are impractical, even if employed in a sufficiently thin resilient membrane to constitute the desired barrier. The various devices of Susuki et al., U.S. Pat. No. 3,360,169 appear to be fairly effective in terms of admitting ambient air for relaxation of the bottle. However, the various geometrics of the disclosed double-layer device, and the double-layer construction itself, appear to be totally impractical for efficient low cost mass production and present sealing, assembly and filling problems.